Cutting tool having releasably mounted self-clamping cutting head

ABSTRACT

A cutting tool has a tool shank and a replaceable cutting head resiliently secured to the tool shank by an interference fit between a male fixation member of the cutting head and a female fixation member of the tool shank. The male fixation member has a resilience slit. In each cross section of the cutting tool taken perpendicular to an axis of rotation of the cutting tool through mutual abutment regions, the cross sectional profiles of the mutual abutment regions are arcuate sectors.

FIELD OF THE INVENTION

The current invention relates to a cutting tool having a releasablymounted cutting head.

BACKGROUND OF THE INVENTION

A drill having a releasably mounted cutting head is disclosed in U.S.Pat. No. 5,228,812. In a first embodiment disclosed in U.S. Pat. No.5,228,812 the drill has an insert portion for cutting a workpiece and ashank portion, the insert portion being separably mechanically connectedto the shank portion. The insert and shank portions have mutuallyengaging portions forming the connection between the insert and theshank, and a slit formed in either the insert or shank engaging portion.The insert portion and the shank portion are connected with each otherusing an elastic force which is caused by an elastic deformation uponmutual movement of the opposite surfaces of the slit in an engagingstate of both portions, whereby the insert portion may be connected withor fixed to the shank portion by press-fitting the insert portion intothe shank portion. In the connected state, the insert is fixed to theshank by frictional force between the side portions of the held portionof the insert and the inner end surfaces of holding portions of theshank.

The drill disclosed in U.S. Pat. No. 5,228,812 is often called a spadedrill which is characterized by an insert portion (i.e., the cuttingportion, or cutting head) having a basically flat shape with twoopposing parallel flat surfaces which is received in a correspondingflat gap formed in the shank. The insert portion and shank portion arebrought into engagement by relative axial displacement of the twocomponents as they are brought together. The insert portion is made of ahard material such as a surface coated cemented carbide and the shank ismade of steel. In order to insure a required accuracy of the opposingparallel flat surfaces, the flat surfaces may be ground. The grindingoperation requires two grinding operations, one when grinding one flatsurface, and another when grinding the other flat surface. Between thetwo grinding operations, the insert portion has to be rotated by 180° inorder to present the non-ground flat surface to the grinding wheel,which may introduce an inaccuracy in the positioning of the non-groundflat surface relative to the grinding wheel.

U.S. Pat. No. 7,306,410 discloses a rotary cutting tool, e.g. a twistdrill, having a tool head made of a hard cutting material, e.g. tungstencarbide, and a tool shank made of a high-speed tool steel or anothermetal material. The tool head has a fixing peg that is coaxial with theaxis of rotation of the tool and which is in the shape of a truncatedcone that tapers toward the tool shank with the axis of rotation as thecone axis. Two spiral flutes divide the surface of the fixing peg intotwo truncated conical generated surfaces that lie essentiallydiametrically opposite each other. The tool shank clamps the replaceabletool head in position on its holding end between the facing flanks oftwo clamping extensions which project essentially in the axial directionfrom the tool shank. The conical generated surfaces of the fixing pegare, in the clamping position, pressed by the facing flanks of the twoclamping extension of the tool shank. The inner flanks which face eachother of the clamping extensions are realized in a concave shapecorresponding to the convex truncated cone generated surfaces of thefixing peg, so that in the fixing position they press with their entiresurfaces against the truncated cone generated surfaces of the fixingpeg.

In an exemplary embodiment illustrated in U.S. Pat. No. 7,306,410 aclamp fixing screw screwed in from the peripheral side of the tool shankruns through the fixing peg and the clamping extensions that clamp it inposition. The clamp fixing screw not only represents a positive-fitconnection between the clamping extensions and the fixing peg, but alsoincreases the clamping pressure which is exerted radially by theclamping extensions on the truncated cone generated surfaces of the peg.In an exemplary embodiment, the clamp fixing screw lies inside a slot,the axis of rotation of which runs diametrically, and which slot runsradially inside the fixing peg and is open toward the tapered end of thefixing peg. The requirement of a clamp fixing screw introduces an extracomplication and longer set up time when securing the replaceable toolhead to the tool shank.

SUMMARY OF THE INVENTION

According to embodiments of the present invention there is provided acutting tool having an axis of rotation around which the cutting toolrotates in a direction of rotation. The cutting tool comprises a toolshank and a replaceable self-clamping cutting head resiliently securedto the tool shank at a tool shank forward end by an interference fitbetween a male fixation member of the cutting head and a female fixationmember of the tool shank. The male and female fixation members are eachconfigured to have abutment regions, the abutment regions on the twofixation members mutually abutting one another. The male fixation memberhas a resilience slit, and in each cross section of the cutting tooltaken perpendicular to the axis of rotation through mutual abutmentregions between the male and female fixation members the cross sectionalprofiles of the mutual abutment regions are mutual arcuate sectors.

In accordance with some embodiments, either the cutting head or the toolshank may be made of cemented carbide. In accordance with otherembodiments, both the cutting head and the tool shank may be made ofcemented carbide.

In accordance with some embodiments, the cutting head comprises acutting portion and a cutting head coupling portion forming a one-piecesingle unitary part with the cutting portion, the cutting head couplingportion comprises the male fixation member extending in a rearwarddirection of the cutting portion and terminating in a cutting headbottom surface. The resilience slit divides the male fixation memberinto two male fixation segments each having a cutting head majorfixation wall forming a peripheral surface bounded by the resilienceslit. The resilience slit opens out to the cutting head major fixationwalls at side apertures and to the cutting head bottom surface at abottom aperture. The side apertures and the bottom aperture meet atbottom aperture ends, the bottom aperture ends are adjacent, but notcoincident with, rotationally trailing edges of respective head flutes.

In accordance with embodiments of the present invention, the tool shankis provided, at its forward end, with a protruding portion having tworotationally spaced apart protrusions extending forwardly from a toolshank bottom surface, and the cutting head bottom surface does not abutthe tool shank bottom surface.

According to some embodiments, a transmission member protrudes from arotationally trailing surface of the cutting head, the transmissionmember having an upper surface facing in an axially forward direction, abase surface facing in an axially rearward direction, and a cutting headtorque transmission wall generally facing opposite the direction ofrotation and located between the upper and base surfaces. The tool shankis provided, at the tool shank forward end, with a protruding portionhaving two rotationally spaced apart protrusions extending forwardlyfrom a tool shank bottom surface, each protrusion comprises a lowerprotruding portion and an upper protruding portion, the lower protrudingportion has an axially forwardly facing axial support surface from whichthe upper protruding portion extends in an axially forward direction,the upper protruding portion and the lower protruding portion form atransmission member receiving recess comprising a tool shank torquetransmission wall generally facing the direction of rotation and anaxially facing axial support surface.

In accordance with some embodiments, the cutting head torquetransmission wall abuts the tool shank torque transmission wall and thebase surface of the transmission member abuts the axial support surfaceproviding axial support to the cutting head.

In accordance with some embodiments, the upper protruding portioncomprises a lower surface generally facing the axial support surface,the tool shank torque transmission wall being located between the lowersurface and the axial support surface, and the upper surface of thetransmission member does not abut the lower surface of the upperprotruding portion.

In another aspect, the present invention is directed to a self-clampingcutting head.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention and to show how thesame may be carried out in practice, reference will now be made to theaccompanying drawings, in which:

FIG. 1 is a perspective view of a cutting tool according to embodimentsof the present invention;

FIG. 2 is an exploded perspective view of the cutting tool of FIG. 1;

FIG. 3 is another exploded perspective view of the cutting tool of FIG.1;

FIG. 4 is yet another exploded perspective view of the cutting tool ofFIG. 1;

FIG. 5 is a perspective view of a the cutting tool of FIG. 1 partiallyassembled;

FIG. 6 is a side view of a the cutting tool of FIG. 1;

FIG. 7 is a cross-sectional view of the cutting tool taken along lineVII-VII in FIG. 6;

FIG. 8 is a cross-sectional view of the cutting tool similar to that ofFIG. 7 but with the cutting head rotated to an intermediate positionrelative to the tool shank;

FIG. 9 is a cross-sectional view of the cutting tool similar to that ofFIG. 7 but with the cutting head rotated by 90° relative to the toolshank; and

FIG. 10 is a bottom view of the cutting head in accordance with someembodiments of the invention.

It will be appreciated that for simplicity and clarity of illustration,elements shown in the figures have not necessarily been drawn accuratelyor to scale. For example, the dimensions of some of the elements may beexaggerated relative to other elements for clarity, or several physicalcomponents may be included in one functional block or element. Further,where considered appropriate, reference numerals may be repeated amongthe figures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, various aspects of the present inventionwill be described. For purposes of explanation, specific configurationsand details are set forth in order to provide a thorough understandingof the present invention. However, it will also be apparent to oneskilled in the art that the present invention may be practiced withoutthe specific details presented herein. Furthermore, well-known featuresmay be omitted or simplified in order not to obscure the presentinvention.

Reference is made to FIG. 1 showing a cutting tool 10 in accordance withembodiments of the present invention. The cutting tool 10 may be adrill, or any other kind of rotary cutting tool. The cutting tool 10includes a cutting head 12 releasably mounted in a self-clamping manneron a tool shank 14 with the cutting head 12 and the tool shank 14 havinga common axis of rotation L around which the cutting tool 10 rotates ina direction of rotation R. The cutting head 12 may be of the sort usedin metal cutting operations and thus can be termed a metal cutting headmeaning that the cutting head may be used for cutting metal, notnecessarily that the cutting head is made of metal. In accordance withsome embodiments, the cutting head 12 may be made of hard wear resistantmaterial such as cemented carbide, and the tool shank 14 may be made ofsteel or of another metal or metal compound. In accordance with someembodiments, the cutting head 12 may be made of a hard wear resistantmaterial such as cemented carbide, and the tool shank 14 may also bemade of a hard wear resistant material such as cemented carbide. Thetool shank 14 may be provided with one or more axially extending shankflutes 16, each of which is fed from a corresponding head flute 18. Theshank and head flutes 16, 18 join to form a tool flute for leading awaychips cut from a workpiece.

In FIGS. 2 to 4, the cutting tool 10 is shown disassembled with thecutting head 12 and the tool shank 14 separated from one another butaligned along the axis of rotation L in preparation for assembly. Theaxis of rotation L defines a forward to rear direction, with the cuttinghead 12 located at an axially forward end of the tool shank 14. Thecutting head 12 comprises a cutting portion 20 and a cutting headcoupling portion 22 forming a one-piece single unitary part with thecutting portion 20.

The cutting head coupling portion 22 comprises a male fixation member 24extending in a rearward direction of the cutting portion 20 andterminating in a cutting head bottom surface 26. A resilience slit 28divides the male fixation member 24 into two male fixation segments 30.Each male fixation segment 30 has a cutting head major fixation wall 32separated from an associated cutting head minor fixation wall 32′ by ahead flute 18 which is recessed relative to the walls 32, 32′. Inaccordance with some embodiments, in the assembled tool, while thecutting head major fixation wall 32 of each male fixation segment 30abuts the tool shank, the cutting head minor fixation wall 32′ does notabut the tool shank. Generally speaking, the cutting head major fixationwall 32 is larger in the circumferential direction than its associatedcutting head minor fixation wall 32′. For a given male fixation segment30, the cutting head major fixation wall 32 forms a peripheral surfacebounded by the resilience slit 28. The resilience slit 28 opens out tothe cutting head major fixation wall 32 and cutting head minor fixationwall 32′ at side apertures 34 and to the cutting head bottom surface 26at a bottom aperture 36. The side apertures 34 and the bottom aperture36 meet at bottom aperture ends 38.

In accordance with some embodiments, the cutting potion 20 comprises tworotationally spaced-apart head segments 40. Each head segment 40 has atop surface 42, a rotationally leading surface 44, facing the directionof rotation R, and a rotationally trailing surface 46, each connected tothe top surface 42. The top surface 42 and the leading surface 44 meetat a cutting edge 48. Protruding from the rotationally trailing surface46 is a transmission member 50 having an upper surface 52 facing in anaxially forward direction, a base surface 54 facing in an axiallyrearward direction, an outwardly facing peripheral surface 56 extendingbetween the upper and base surfaces 52, 54 and a cutting head torquetransmission wall 58 generally facing opposite the direction of rotationR and located between the upper and base surfaces 52, 54.

The tool shank 14 has a tool shank forward end 60 in which the cuttinghead 12 is releasably mounted. In accordance with some embodiments, atthe tool shank forward end 60, the tool shank 14 is provided with aprotruding portion 62 having two rotationally spaced apart protrusions64 extending forwardly from a tool shank bottom surface 66. Eachprotrusion 64 comprises a lower protruding portion 68 and an upperprotruding portion 70. The lower protruding portion 68 has an axiallyforwardly facing axial support surface 72 from which the upperprotruding portion 70 extends in an axially forward direction. The upperprotruding portion 70 may be generally hook-shaped and bounded by afirst surface 74 generally facing opposite the direction of rotation R,a second surface 76 joining the first surface 74 and generally facing inan axially forward direction, a third surface 78 joining the secondsurface 76 and generally facing the direction of rotation R, a lowersurface 80 joining the third surface 78 and generally facing the axialsupport surface 72 and a tool shank torque transmission wall 82generally facing the direction of rotation R and located between thelower surface 80 and the axial support surface 72. The lower surface 80,tool shank torque transmission wall 82 and axial support surface 72 formbetween them an opening which defines a transmission member receivingrecess 84.

A tool shank coupling portion 86 is located at the tool shank forwardend 60. The tool shank coupling portion 86 comprises a female fixationmember 88 in the form of a tool shank pocket recess 90 bound by two toolshank fixation walls 92 which are inner peripheral surfaces of the lowerprotruding portions 68 and are separated by tool shank peripheralapertures 94. The tool shank fixation walls 92 extend away from the toolshank bottom surface 66.

In accordance with some embodiments, the cutting head major and toolshank fixation walls 32, 92 are arcuate in shape. In accordance withsome embodiments, at least portions of one or both of the cutting headmajor and tool fixation walls 32, 92 lay on a cylindrical surface.

In FIG. 5, the cutting tool is partially assembled with the cutting head12 and the tool shank 14 having been brought together along the axis ofrotation L from their relative positions shown in FIG. 2. Thus, in FIG.5, the cutting head 12 and the tool shank 14 are in the same rotationalorientation about the axis of rotation L, as seen in FIG. 2, but withthe male fixation member 24 located in the female fixation member 88.

In FIG. 6 the cutting tool 10 is shown assembled with the cutting head12 securely clamped in the tool shank 14. The assembled cutting tool 10is obtained from the partially assembled configuration shown in FIG. 5by rotating the cutting head 12 in a direction opposite the direction ofrotation R, relative to the tool shank 14 with the transmission member50 located in the transmission member receiving recess 84 until thecutting head torque transmission wall 58 abuts the tool shank torquetransmission wall 82. In the assembled configuration, in addition to thecutting head torque transmission wall 58 abutting the tool shank torquetransmission wall 82, the base surface 54 of the transmission member 50abuts the axial support surface 72 providing axial support to thecutting head 12. In accordance with some embodiments, the cutting headbottom surface 26 does not abut the tool shank bottom surface 66 and theupper surface 52 of the transmission member 50 does not abut the lowersurface 80 of the upper protruding portion 70.

Attention is now drawn to FIG. 7 showing a cross section of the cuttingtool 10 taken perpendicular to the axis of rotation L in the lowerprotruding portion 68 of the tool shank coupling portion 86 andconsequently through the male fixation member 24 of the cutting head 12.In some embodiments, in such a cross section each of the cutting headmajor fixation walls 32 has a head fixation wall arcuate sector 96 oflength S1, and each of the tool shank fixation walls 92 has a tool shankfixation wall arcuate sector 98 of length S2. In some embodiments thelength S2 is greater than length S1.

In some embodiments, in any given cross section, each of the cuttinghead major fixation walls 32 may have a circular sector of a givenlength. In some embodiments, the given length of each of the arcuate orcircular sectors may be different in different cross sections. In someembodiments, in any given cross section the whole length of each of thecutting head major fixation walls 32 may be an arcuate or circularsector. Similarly, in some embodiments, in any particular cross sectioneach of the tool shank fixation walls 92 may have an arcuate or circularsector of a particular length. In some embodiments, the particularlength of the arcuate or circular sector may be different in differentcross sections. In some embodiments, in any particular cross section thewhole length of each of the tool shank fixation walls 92 may be anarcuate or circular sector.

As shown in FIG. 7, the male and female fixation members 24, 88 areconfigured such that, in the assembled tool, they abut each other atmutual abutment regions 100. In some embodiments, on the male fixationmember, only the cutting head major fixation walls 32, and not thecutting head minor fixation walls 32′ are configured to have abutmentregions. In some embodiments, a given cutting head major fixation wall32 abuts a corresponding tool shank fixation wall 92 at only one mutualabutment region 100. It is understood, however, that the axial extent ofany such mutual abutment region 100 along the axis of rotation L neednot extend along the entire length of the cutting head major fixationwall 32. In each cross section of the cutting tool 10 taken throughmutual abutment regions 100 perpendicular to the axis of rotation L thecross sectional profiles of the mutual abutment regions 100 may bemutual arcuate sectors. In some embodiments, the mutual arcuate sectorsmay be circular sectors.

The male and female fixation members 24, 88 are designed to have aninterference fit between them so that in the assembled configuration(FIGS. 6 and 7) the male fixation member 24 is securely held in thefemale fixation member 88. Such an interference fit between the male andfemale fixation members 24, 88 is achieved by designing the male andfemale fixation members 24, 88 so that the diameter of the male fixationmember 24 is larger than the diameter of the female fixation member 88at least some portions of the mutual abutment regions 100. Theresilience slit 28 provides flexibility to the male fixation member 24enabling the diameter of the male fixation member 24 (that is, thediameter in any cross section of the male fixation member 24 takenperpendicular to the axis of rotation L and through the resilience slit28) to be made smaller by applying a force perpendicular to theresilience slit 28. On applying such a force the two male fixationsegments 30 are moved closer to each other and a resilience force is setup in the male fixation member 24 which urges the male fixation segments30 apart to their original position. If the applied force is notperpendicular to the resilience slit 28 then the force required to causea given reduction in diameter will be greater.

In order to remove the cutting head 12 from the tool shank 14 from theassembled configuration as shown in FIG. 7, the cutting head 12 isrotated, relative to the tool shank 14, in the direction of rotation Rby 90°, via an intermediate position shown in FIG. 8, to a partiallyassembled configuration shown in FIG. 9, which is equivalent to theconfiguration shown in FIG. 5. In the partially assembled configurationshown in FIG. 9 the cutting head 12 can be removed from the tool shank14 by moving the cutting head 12 and tool shank 14 apart along the axisof rotation L arriving at the dismantled configuration shown in FIG. 2.

In order to mount the cutting head 12 on the tool shank 14 and securelyaffix it thereto, a set of operations opposite to that described aboveis performed. That is, starting from the disassembled configurationshown in FIG. 2 with the cutting head 12 and the tool shank 14 separatedfrom one another but aligned along the axis of rotation L the cuttinghead 12 and the tool shank 14 are brought together along the axis ofrotation L until the male fixation member 24 is located in the femalefixation member 88 as shown in FIG. 9. The cutting head 12 is thenrotated, relative to the tool shank 14, in the direction opposite thedirection of rotation R, by 90°, via the intermediate position shown inFIG. 8, to the assembled configuration shown in FIG. 7.

In some embodiments, the intermediate position shown in FIG. 8 is theposition of first contact between the cutting head 12 and the tool shank14 during the assembly of the cutting tool 10. In such embodiments, thepoint of first contact between the cutting head major fixation walls 32and the tool shank fixation walls 92 during the assembly of the cuttingtool 10 is not between a leading extremity 104 of each of the cuttinghead major fixation walls 32 and an associated trailing extremity 106 ofeach of the tool shank fixation walls 92 but between the leadingextremity 104 of each of the cutting head major fixation walls 32 and aninner point 108 on each associated tool shank fixation wall 92. In someembodiments, this is achieved by forming chamfered portions 110 at anadjacent the trailing extremity 106 of each of the tool shank fixationwalls 92. Consequently, during assembly, initial frictional contactbetween the male and female fixation members 24, 88 is made along thehead and tool shank fixation wall arcuate sectors 96, 98 (or, circularsectors in some embodiments), starting at the circumferentially innerpoint 108 of each tool shank fixation wall 92 (in a given crosssection), but is avoided at the chamfered portions 110.

As the male fixation member 24 is rotated from the partially assembledconfiguration (FIGS. 5 and 9) by rotating the cutting head 12 in adirection opposite the direction of rotation R relative to the toolshank 14, the male fixation segments 30 are forced towards each othersince the diameter of the male fixations member 24 is initially largerthan the diameter of the female fixation member 88 and a resilienceforce is set up in the male fixation member 24. Consequently, force hasto be applied to rotate the cutting head 12 relative to the tool shank14 to overcome frictional forces acting between the two.

In accordance with some embodiments, the resilience slit 28 is directedso that during initial contact between the leading extremity 104 of eachof the cutting head major fixation walls 32 and the inner point 108 oneach associated tool shank fixation wall 92, the force F acting on themale fixation member 24, to overcome the resilience force, issubstantially perpendicular to the resilience slit 28 (see FIG. 8),whereby the force required to rotate the cutting head 12 relative to thetool shank 14 is less than if the force acting on the male fixationmember 24 was not substantially perpendicular to the resilience slit 28.Moreover, with the resilience slit 28 directed as shown in the figures,the resilience slit 28 does not open out to the head flute 18 andtherefore in the assembled configuration of the cutting tool 10, asshown in FIG. 1, chips cut from a workpiece cannot enter the resilienceslit 28.

Attention is now drawn to FIG. 10 showing a bottom view of the cuttinghead 12 showing the orientation of the resilience slit 28 in accordancewith some embodiments of the invention. In accordance with someembodiments, the bottom aperture ends 38 are adjacent, but notcoincident with, rotationally trailing edges 112 of respective headflutes 18.

While the present invention has been described with reference to one ormore specific embodiments, the description is intended to beillustrative as a whole and is not to be construed as limiting theinvention to the embodiments shown. It is appreciated that variousmodifications may occur to those skilled in the art that, while notspecifically shown herein, are nevertheless within the scope of theinvention.

What is claimed is:
 1. A cutting tool (10) having an axis of rotation(L) around which the cutting tool (10) rotates in a direction ofrotation (R), the cutting tool (10) comprising: a tool shank (14) havinga forward end (60) provided with a female fixation member (88); and areplaceable self-clamping cutting head (12) provided with a malefixation member (24); wherein: the male fixation member (24) has aresilience slit (28); the replaceable cutting head is resilientlysecured to the forward end (60) of the tool shank (14) by aninterference fit between the male fixation member (24) and the femalefixation member (88) at mutual abutment regions (100); in each crosssection of the cutting tool (10) taken perpendicular to the axis ofrotation (L) through the mutual abutment regions (100), cross sectionalprofiles of the mutual abutment regions (100) comprise mutual arcuatesectors; a transmission member (50) protrudes from a rotationallytrailing surface (46) of the cutting head (12); the transmission member(50) has an upper surface (52) facing in an axially forward direction, abase surface (54) facing in an axially rearward direction, and a cuttinghead torque transmission wall (58) generally facing opposite thedirection of rotation (R) and located between the upper and basesurfaces (52, 54).
 2. The cutting tool according to claim 1, wherein thecutting head (12) is made of cemented carbide.
 3. The cutting toolaccording to claim 1, wherein the tool shank (14) is made of cementedcarbide.
 4. The cutting tool according to claim 1, wherein the cuttinghead (12) and the tool shank (14) are made of cemented carbide.
 5. Thecutting tool according to claim 1, wherein the mutual arcuate sectorsare mutual circular sectors.
 6. The cutting tool according to claim 1,wherein: the cutting head (12) comprises a cutting portion (20) and acutting head coupling portion (22) forming a one-piece single unitarypart with the cutting portion (20); the cutting head coupling portion(22) comprises the male fixation member (24) extending in a rearwarddirection of the cutting portion (20) and terminating in a cutting headbottom surface (26); the resilience slit (28) divides the male fixationmember (24) into two male fixation segments (30) each having a cuttinghead major fixation wall (32) forming a peripheral surface bounded bythe resilience slit (28); and the resilience slit (28) opens out to thecutting head major fixation walls (32) at side apertures (34) and to thecutting head bottom surface (26) at a bottom aperture (36).
 7. Thecutting tool according to claim 6, wherein: the side apertures (34) andthe bottom aperture (36) meet at bottom aperture ends (38); and thebottom aperture ends (38) are adjacent, but not coincident with,rotationally trailing edges (112) of respective head flutes (18).
 8. Thecutting tool according to claim 6, wherein: the tool shank (14) isprovided, at the tool shank forward end (60), with a protruding portion(62) having two rotationally spaced apart protrusions (64) extendingforwardly from a tool shank bottom surface (66); and the cutting headbottom surface (26) does not abut the tool shank bottom surface (66). 9.The cutting tool according to claim 1, wherein: the tool shank (14) isprovided, at the tool shank forward end (60), with a protruding portion(62) having two rotationally spaced apart protrusions (64) extendingforwardly from a tool shank bottom surface (66); each protrusion (64)comprises a lower protruding portion (68) and an upper protrudingportion (70); the lower protruding portion (68) has an axially forwardlyfacing axial support surface (72) from which the upper protrudingportion (70) extends in an axially forward direction; the upperprotruding portion (70) and the lower protruding portion (68) form atransmission member receiving recess (84) comprising a tool shank torquetransmission wall (82) generally facing the direction of rotation (R)and an axially facing axial support surface (72); the cutting headtorque transmission wall (58) abuts the tool shank torque transmissionwall (82); and the base surface (54) of the transmission member (50)abuts the axial support surface (72) providing axial support to thecutting head (12).
 10. The cutting tool according to claim 9, wherein:the upper protruding portion (70) comprises a lower surface (80)generally facing the axial support surface (72); the tool shank torquetransmission wall (82) is located between the lower surface (80) and theaxial support surface (72); and the upper surface (52) of thetransmission member (50) does not abut the lower surface (80) of theupper protruding portion (70).
 11. A cutting tool (10) having an axis ofrotation (L) around which the cutting tool (10) rotates in a directionof rotation (R), the cutting tool (10) comprising: a tool shank (14)having a forward end (60) provided with a female fixation member (88);and a replaceable self-clamping cutting head (12) provided with a malefixation member (24); wherein: the male fixation member (24) has aresilience slit (28); the replaceable cutting head is resilientlysecured to the forward end (60) of the tool shank (14) by aninterference fit between the male fixation member (24) and the femalefixation member (88) at mutual abutment regions (100); in each crosssection of the cutting tool (10) taken perpendicular to the axis ofrotation (L) through the mutual abutment regions (100), cross sectionalprofiles of the mutual abutment regions (100) comprise mutual arcuatesectors; the resilience slit (28) divides the male fixation member (24)into two male fixation segments (30) each having a cutting head majorfixation wall (32); the female fixation member (88) comprises two toolshank fixation walls (92); each cutting head major fixation wall (32)abuts a corresponding tool shank fixation wall (92); and a trailingextremity (106) of each tool shank fixation wall (92) is provided with achamfered portion (110) so that, during assembly, initial frictionalcontact between the cutting head major fixation walls (32) and the toolshank fixation walls (92) starts at a circumferentially inner point(108) along each tool shank fixation wall (92).
 12. A cutting tool (10)having an axis of rotation (L) around which the cutting tool (10)rotates in a direction of rotation (R), the cutting tool (10)comprising: a tool shank (14) having a forward end (60) provided with afemale fixation member (88); and a replaceable self-clamping cuttinghead (12) provided with a male fixation member (24); wherein: the malefixation member (24) has a resilience slit (28); the replaceable cuttinghead is resiliently secured to the forward end (60) of the tool shank(14) by an interference fit between the male fixation member (24) andthe female fixation member (88) at mutual abutment regions (100); ineach cross section of the cutting tool (10) taken perpendicular to theaxis of rotation (L) through the mutual abutment regions (100), crosssectional profiles of the mutual abutment regions (100) comprise mutualarcuate sectors; the cutting head (20) has a head flute (18) whichextends in a rearward direction into a periphery of the male fixationmember (24); the resilience slit (28) divides the male fixation member(24) into two male fixation segments (30); each male fixation segment(30) comprises a cutting head major fixation wall (32) separated from anassociated cutting head minor fixation wall (32′) by the head flute(18).
 13. The cutting tool according to claim 12, wherein: the cuttinghead major fixation walls (32) abut the tool shank (14); and the cuttinghead minor fixation walls (32′) do not abut the tool shank (14).
 14. Thecutting tool according to claim 12, wherein: in a given male fixationsegment (30), the cutting major head fixation wall (32) is larger in acircumferential direction than its associated cutting head minorfixation wall (32′).
 15. The cutting tool according to claim 12,wherein: the resilience slit (28) comprises side apertures (34) and abottom aperture (36) which meet at bottom aperture ends (38); and thebottom aperture ends (38) are adjacent, but not coincident with,rotationally leading edges (112) of respective head flutes (18).
 16. Thecutting tool according to claim 12, wherein: a transmission member (50)protrudes from a rotationally trailing surface (46) of the cutting head(12); the transmission member (50) has an upper surface (52) facing inan axially forward direction, a base surface (54) facing in an axiallyrearward direction, and a cutting head torque transmission wall (58)generally facing opposite the direction of rotation (R) and locatedbetween the upper and base surfaces (52, 54).
 17. The cutting toolaccording to claim 16, wherein: the tool shank (14) is provided, at thetool shank forward end (60), with a protruding portion (62) having tworotationally spaced apart protrusions (64) extending forwardly from atool shank bottom surface (66); each protrusion (64) comprises a lowerprotruding portion (68) and an upper protruding portion (70); the lowerprotruding portion (68) has an axially forwardly facing axial supportsurface (72) from which the upper protruding portion (70) extends in anaxially forward direction; the upper protruding portion (70) and thelower protruding portion (68) form a transmission member receivingrecess (84) comprising a tool shank torque transmission wall (82)generally facing the direction of rotation (R) and an axially facingaxial support surface (72); the cutting head torque transmission wall(58) abuts the tool shank torque transmission wall (82); and the basesurface (54) of the transmission member (50) abuts the axial supportsurface (72) providing axial support to the cutting head (12).
 18. Thecutting tool according to claim 17, wherein: the upper protrudingportion (70) comprises a lower surface (80) generally facing the axialsupport surface (72); the tool shank torque transmission wall (82) islocated between the lower surface (80) and the axial support surface(72); and the upper surface (52) of the transmission member (50) doesnot abut the lower surface (80) of the upper protruding portion (70).19. A cutting tool (10) having an axis of rotation (L) around which thecutting tool (10) rotates in a direction of rotation (R), the cuttingtool (10) comprising: a tool shank (14) having a forward end (60)provided with a female fixation member (88); and a self-clamping cuttinghead (12) comprising: a cutting portion (20); a cutting head couplingportion (22) forming a one-piece single unitary part with the cuttingportion (20), the cutting head coupling portion (22) comprising a malefixation member (24) extending in a rearward direction of the cuttingportion (20) and terminating in a cutting head bottom surface (26); headflutes (18) extending in a rearward direction into a periphery of themale fixation member (24); and a resilience slit (28) dividing the malefixation member (24) into two male fixation segments (30); wherein: eachmale fixation segment (30) comprises a cutting head major fixation wall(32) separated from an associated cutting head minor fixation wall (32′)by one of the head flutes (18); wherein: the self-clamping cutting headis resiliently secured to the forward end (60) of the tool shank (14) byan interference fit between the male fixation member (24) and the femalefixation member (88) at mutual abutment regions (100); and in each crosssection of the cutting tool (10) taken perpendicular to the axis ofrotation (L) through the mutual abutment regions (100), cross sectionalprofiles of the mutual abutment regions (100) comprise mutual arcuatesectors.
 20. The cutting tool according to claim 19, wherein: atransmission member (50) protrudes from a rotationally trailing surface(46) of the cutting head (12); the transmission member (50) has an uppersurface (52) facing in an axially forward direction, a base surface (54)facing in an axially rearward direction, and a cutting head torquetransmission wall (58) generally facing opposite the direction ofrotation (R) and located between the upper and base surfaces (52, 54).21. The cutting tool according to claim 20, wherein: the tool shank (14)is provided, at the tool shank forward end (60), with a protrudingportion (62) having two rotationally spaced apart protrusions (64)extending forwardly from a tool shank bottom surface (66); eachprotrusion (64) comprises a lower protruding portion (68) and an upperprotruding portion (70); the lower protruding portion (68) has anaxially forwardly facing axial support surface (72) from which the upperprotruding portion (70) extends in an axially forward direction; theupper protruding portion (70) and the lower protruding portion (68) forma transmission member receiving recess (84) comprising a tool shanktorque transmission wall (82) generally facing the direction of rotation(R) and an axially facing axial support surface (72); the cutting headtorque transmission wall (58) abuts the tool shank torque transmissionwall (82); and the base surface (54) of the transmission member (50)abuts the axial support surface (72) providing axial support to thecutting head (12).
 22. The cutting tool according to claim 21, wherein:the upper protruding portion (70) comprises a lower surface (80)generally facing the axial support surface (72); the tool shank torquetransmission wall (82) is located between the lower surface (80) and theaxial support surface (72); and the upper surface (52) of thetransmission member (50) does not abut the lower surface (80) of theupper protruding portion (70).